Everything
will feel faster! You can't go back to IDE after that.The JoJo

My five year old Cheetah Mark 1 is still more responsive than any IDE
drive yet made, and will remain so until IDE access times improve. Of those who
go SCSI, very few ever go back. You buy one SCSI rig and you can expect you'll
buy others as the years go by - because once you get to know the power of fine
SCSI drives, you'll never feel satisfied with IDE drives again. Most of the
benefit in SCSI drives - if pushed to put a figure on it, I'd say 70 or 80% - is
due to their superior seek times and lower latency.Tannin

I made the
switch, and I don't believe I would go back to EIDE. Only if I needed mass
storage at a cheap price, but this is not the case. When I moved from my WD
Expert drive to my Atlas 10KII, what a difference. Just in converting MP3's to
wav it was awesome. I even sit and watch defrag run sometimes because it screams
right by. SCSI isn't for everyone, but for those do use it will notice the
difference.Handruin

I just got my first SCSI rig, an IBM 36LZX (18.4GB) on a Tekram DC-390U3W card.
It is MUCH more responsive than my old IDE system. I also appreciate
SCSI's fringe benefits. I can use one channel of my current card for SCSI
CD-ROMs, etc., but I prefer to use ATAPI, since they tend to be a cheaper, and
there isn't any performance difference for equivalent models. Using a SCSI boot
drive, I have 2 free IDE channels. I can put a CD-ROM on one, a CD-RW on the
other. This allows me to copy from one to the other. I could also add cheap,
huge IDE storage IDE drives.

I will never again build a system with an IDE boot drive. The 10K RPM drives are
reasonably cheap these days, running well under US$200, and once you get a card
and drive, it will last you for a LONG time, from what I have heard...so the
cost does have some mitigating factors.

All in all, I'm VERY happy with my SCSI rig...I think you will be too. If you're
looking for "feel," then 10k RPM will give it to you. Only go 15k if
you put your system under heavy stress, or if you have a large budget (I
don't...sigh)balding_ape

It is not just the low access times. The SCSI interface is far more intelligent
than IDE, capable of queuing I/O requests and reordering them on the fly to
optimize performance. Therefore, SCSI shines in multitasking environments. For
example, if you have several processes running, accessing your drive at the same
time and in different places, SCSI will run smooth in situations where IDE gets
bogged down.

If you were to ask for a single word characterization, I would sum it up by
saying that the low access times contribute to "responsiveness," while
the multitasking capabilities create that great feeling of
"smoothness."leokor

Before closing, I want to
mention <shamelessly pimp> a few other Radified guides that you
might find helpful. For example: